Liberal governments in New South Wales and Victoria look set to butt heads with their federal colleagues over the "Gonski" school funding agreements.

Education Minister Christopher Pyne has said the Coalition cannot go ahead with the "Gonski" funding arrangements and will go back to the "drawing board".

He insists the total amount of money allocated to schools funding will not change, but says he will seek to introduce a new funding model in 2015.

"I'm committed to the same funding envelope as the previous government. But what I'm not going to proceed with is a school funding model that is inequitable and utterly incomprehensible," he told PM yesterday.

"It's time to fix it, and I intend to do just that. But I also intend to ensure that states, whether they're signatory states or non-signatory states, are treated fairly."

But NSW and Victoria are among those insisting that agreements for funding over the next six years are signed off.

NSW Education Minister Adrian Piccoli says the state already has a "binding agreement" that must be honoured.

"NSW expects the Commonwealth to fulfil its obligations under this agreement," he told Lateline last night.

"NSW will not agree to returning to the broken SES funding model. The new funding model has secured additional resources for classrooms across NSW, with the majority going to schools in most need."

Mr Piccoli said his Government - which was the first to sign up to former prime minister Julia Gillard's funding plan - has already applied the new model to the state's 2,200 schools.

"Any attempt to change the model now may see both government and non-government schools lose funding," he added.

"I've spoken to Minister Pyne about this on a number of occasions," he went on. "I do share some of his concerns around compliance, red tape, etc, but we are implementing in public schools here in New South Wales a needs-based funding model and it's been resoundingly welcomed by parents and school communities.

"I'm such a strong supporter of a needs-based funding model because it's not just an educational issue, this is a social issue for Australia, it's an economic issue and to a large degree it's a moral issue as well."

Mr Pyne said agreements with Victoria, Tasmania and the Catholic education system did not advance beyond the first stage and will have to be revised.

Labor leader Bill Shorten, who was education minister at the time many of the agreements were announced, is adamant an agreement was made with Victoria because he was involved in the negotiations.

In a statement, Victoria's Education Minister Martin Dixon has said his state's $12.2 billion agreement must stand, saying "along with Victorian schools and school communities, we expect the Commonwealth to honour this funding".

While a heads of agreement was signed between Tasmania and the Labor government, a binding bilateral agreement was not finalised.

The Education Minister Nick McKim says he is trying to find out from Mr Pyne what changes he intends to make.

But the head of the National Catholic Education Commission, Ross Fox, has written to his colleagues to dispute that.

He says the previous Labor Government received legal advice that a formal legal contract was not appropriate.

The letter from Mr Fox also reveals the Catholic Education Commission met with the Coalition Government's commission of audit last week.

He says they discussed the sustainability of school funding under the Gonski model.

Mr Shorten says the Coalition is breaking its promises.

"Tony Abbott said they were on a unity ticket with the then Labor government about supporting education funding and making sure that education funding, based according to children's individual needs and the needs of schools, was not a political football," he said.

But Bill Daniels from the Independent Schools Council says Labor's funding model would have been difficult to put in place and he is open to change.

"We would be seeking from the Coalition Government the same commitment we got from the Gillard government that no school would be worse off at the end of any review process."

Greens hopeful of finding 'common ground' on school funding

The Greens, which hold the balance of the power in the Senate until July, are vowing to block any changes in parliament.

Greens education spokeswoman Penny Wright says the Coalition will have to take legislation or regulatory change to the parliament for approval.

Even when the Senate change over happens on July 1, Senator Wright is hopeful of winning support from new senators.

"I'm sure that we will be able to find some common ground with some of the new senators about the need to make sure we have a fair school funding system, that means that every single kid has a chance to reach their potential irrespective of where they live or what their postcode or their family circumstances are," she said.